The cost of all tickets and passes for the Rome public transportation system is going up on May 25th. If you have a ticket or pass bought before the price increase, you can use it until July 31st. From August 1st to October 31st, you can exchange it for a new ticket or pass, paying the difference. After that, you need to throw it out.
The new prices are:
BIT (Single tickets) - €1.50 (now good for 100 minutes rather than 75)
BIG day pass .- €6 (break even at 4 trips)
BTI 3-day pass - €16.50 (break even at 11 trips)
CIS 7-day pass - €24 (break even at 16 trips)
The regional BIRG passes will also go up. The 3-zone pass (also called Zone C pass) will be €8, instead of €6. This is the pass that is good as far as Tivoli. The 5-zone (zone E) pass, which was used for trips to the cruise port at Civitavecchia will be €12 instead of €9. 4 zones will be €9.30, and six and seven zone will be €14.